Dynamic flexibility correlation with

Solvent polarity is known to affect catalytic activity, yet consistent correlations between activity and solvent dielectric (e) have not been observed [12,102]. However, a striking correlation was found between the catalytic efficiency of salt-activated subtilisin Carlsberg and the mobility of water molecules (as determined using NMR relaxation techniques) associated with the enzyme in solvents of varying polarities (Figure 3.11) [103]. As the solvent polarity increased, the water mobility of the enzyme increased, yet the catalytic activity of the enzyme decreased. This is consistent with previous EPR and molecular dynamics (MD) studies, which indicated that enzyme flexibility increases with increasing solvent dielectric [104]. 

Eppler et al. [103] viewed these results as having a potential relationship to salt-activated enzyme preparations, particularly in relation to the mobility of enzyme-bound water. Specifically, the authors examined both water mobility [as measured by T2-derived correlation times, (tc)D20] and NaF-activated enzyme activity and observed a linear relationship. This suggests that the salt-activated enzymes contain a more mobile water population than salt-free enzymes, which facilitates a more aqueous-like local environment and dramatically increases enzyme activity through increased flexibility. Therefore, enzyme activation appears to correlate with the properties of enzyme-associated water. Once again, the physicochemical properties of water dictate enzyme structure, function, and dynamics. Hence, salt activation has proven to be a useful technique in activating enzymes for use in organic solvents and has provided a quantitative tool to better understand the role of water in enzymatic catalysis in dehydrated media. 

The above shown structure has amesogenic core, (hard central segment) correlated with dynamic packing of anisometric shapes. The flexible tales, often hydrocarbon chains, extend from the mesogenic core and facihtate the transformatirHi from the sohd state to the liquid crystaUine phase. 2. A calamitic liquid crystal... 

Skopalik J, Anzenbacher P, Otyepka M (2008) Flexibility of human cytochromes P450 molecular dynamics reveals differences between CYPs 3A4, 2C9, and 2A6, which correlate with their substrate preferences. J Phys Chem B 112 8165-8173... 

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